1. Field of the Invention
This invention relates to synthetic ester lubricant base stocks, more particularly to carboxylic acid esters of technical pentaerythriotol.
2. Background of the Invention
Synthetic ester base stocks for use in lubricant formulations are well known. One important factor for synthetic ester base stocks used in jet engine lubricants is the tendency of the esters to form deposits at high temperatures. This tendency to form deposits is particularly important to modern jet engines which operate under more severe requirements, e.g., higher operating temperatures.
U.S. Pat. No. 4,826,633 is directed to synthetic ester base stocks which do not contain esters of dipentaerythritol and which provide lubricant formulations having acceptable viscosity and pour point characteristics. Esters of monopentaerythritol are stated to provide synthetic ester lubricants which exhibit reduced tendency to form deposits whereas esters of dipentaerythritol lead to increased tendency to form deposits.
Because of the increased demands placed on synthetic lubricants by modern jet engines, there is a need for synthetic ester base stocks which have even further reduced tendencies to form deposits under operating conditions.